Strain and strain rate biochemical feedback on the mechanics of epithelial tissues*

The feedback between mechanical and chemical signals plays a key role in controlling many biological processes and collective cell behavior. Here we focus on the emergence of spatiotemporal density waves ubiquitously observed in the collective migration of expanding tissue monolayers and in their rheological response to external forces. Continuum models describing biological tissues as active viscoelastic media with mechano-chemical couplings between cell tension and myosin activation have been shown to capture the emergence of traveling waves of cell density. Whether cytoskeletal myosin responds to cell strain, cell strain rate or changes in overall cell size remains, however, controversial. We address this question in the context of a minimal 1D model of a cell train by examining the behavior of an unperturbed tissue and its response to static step strain and oscillatory boundary perturbation in constrained geometries.